Not a lot of Facebook people on HN these days. Or at least they don't reveal it.

Apple people were notorious for being on HN, and never revealing who they were. After a while, the Facebook people all went silent. Then most of the Google people, though there are still a few here and there that will let you know.

It's like the FAANG employees all got the same memo about not revealing who they are. Or they got tired of trying to be helpful to only receive hundreds of off-topic replies from people grinding axes.